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Risk Assessment: Soil and Soil Gas
Human-Exposure-Based Screening Numbers Developed to Aid Estimation of Cleanup Costs for Contaminated Soil - January 2005 revision
and Excel-based calculator for Hazard Index and Risk Index (calculator updated 4/04/05)
Calculator removed [02/11/14]
The Office of Environmental Health Hazard Assessment (OEHHA) of the California Environmental Protection Agency announces the availability of the report, “Human-Exposure-Based Screening Numbers Developed to Aid Estimation of Cleanup Costs for Contaminated Soil, January 2005 revision”. This report is required by the California Land Environmental Restoration and Reuse Act (Escutia, Chapter 764, Statues of 2001) as part of the effort to develop soil screening numbers for a specific set of contaminants. The Act identifies a screening number as solely an advisory number , and has no regulatory effect. The screening numbers are intended to enable citizen groups, community organizations, property owners, developers, and local government officials to estimate the degree of effort that may be necessary to remediate a contaminated property. This document does not discuss how the public and government agencies might apply these screening numbers, once they are developed. The document is limited to the technical basis that will be used to compute the screening numbers.
In addition, we are providing this Microsoft Excel-based calculator as a tool to assist in calculating the Hazard Index and Risk Index based on soil concentrations and/or soil gas concentrations using the California Human Health Screening Levels. This calculator was developed in response to concerns that the CHHSLs do not account for the presence of multiple contaminants, but require calculation of a hazard index and risk index when multiple contaminants are present at a site.
The calculator is for your personal use. While we believe it will provide accurate results when used as designed and intended, it is the responsibility of the user to verify the results. The California Environmental Protection Agency and its boards, department and offices are not responsible for any decisions, actions, or conclusions taken or made based on the results obtained using the calculator.
The calculator was created using Microsoft Excel 2000. When opening the file, the user must click on “Enable Macros” for the calculator to work. Problems encountered or suggestions for improving the calculator should be sent to firstname.lastname@example.org. This calculator is meant as an aid and is not part of the document.
Follow this link for Cal/EPA guidance, including the screening values and important information on how they are to be used.